Fix Ruff badge URL in README (#1434)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: fepegar

README.md

@@ -53,7 +53,7 @@ at [OpenAI](https://openai.com/) ([link](https://jack-clark.net/2020/03/17/)).
         </td>
         <td align="center">
             <a href="https://docs.astral.sh/ruff/">
-                <img src="https://camo.githubusercontent.com/bb88127790fb054cba2caf3f3be2569c1b97bb45a44b47b52d738f8781a8ede4/68747470733a2f2f696d672e736869656c64732e696f2f656e64706f696e743f75726c3d68747470733a2f2f7261772e67697468756275736572636f6e74656e742e636f6d2f636861726c6965726d617273682f727566662f6d61696e2f6173736574732f62616467652f76312e6a736f6e" alt="Code style">
+                <img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/charliermarsh/ruff/main/assets/badge/v1.json" alt="Code style">
             </a>
             <a href="https://scrutinizer-ci.com/g/TorchIO-project/torchio/?branch=main">
                 <img src="https://img.shields.io/scrutinizer/g/TorchIO-project/torchio.svg?label=Code%20quality&logo=scrutinizer" alt="Code quality">